1. Field of the Invention
The present invention relates in general to a digital broadcasting service technology and, more particularly, to a method and apparatus for a digital broadcasting service allowing direct and real-time control of a digital broadcasting receiver.
2. Description of the Related Art
Generally, a broadcasting service is provided to all users who have suitable receiving terminals. Such broadcasting services may be classified into an audio broadcasting service that offers audio only, a video-centered broadcasting service that offers video as well as audio, and a multimedia broadcasting service that offers audio, video and data all together. Although traditional broadcasting services have been based on analog systems, most broadcasting services today are digital, with dramatic advances in related technologies. In addition, surpassing the conventional broadcast systems centered on a transmission tower, modern broadcasting services are making a growth toward various systems employing wired networks, wireless networks, and artificial satellites, alone or in connection with each other. Particularly, with the advent of mobile communication technology, current broadcasting systems are gradually merged with mobile communication systems.
A Digital Video Broadcasting (DVB) system, one of the existing broadcast systems which provide digital broadcasting services, may employ a conditional access message to restrictively provide broadcasting services for particular content or to specific end users. Such a conditional access message may include an Entitlement Management Message (EMM) and an Entitlement Control Message (ECM).
The EMM manages a subscriber's access authority. On the other hand, the ECM selectively offers given content to a specially qualified subscriber. Namely, the ECM refers to a message that represents conditional access properties of individual content. Such an ECM contains a control word necessary for descrambling content at a receiver. Specifically, in order to restrict a broadcasting service for a normal subscriber, a service provider performs encryption of particular content through scrambling before sending the content to a subscriber's receiver. Then the receiver which receives a broadcasting service can obtain a control word for descrambling in the case of only purchasing the scrambled content.
However, such conditional access messages may fail to directly control the receiver, and also, may restrict a service by content only. Therefore, a method for controlling the digital broadcasting receiver is required so as to provide various and interactive services to end users.